4L80E problems

I have a 2003 2500hd GMC Sierra 4x4 with 6.0L and a 4L80E. Im having some quirky problems with the torque converter lock up. It will lock in and out continuously while pulling hills with a trailer. I've unplugged my brake controller and changed the brake switch. No change. I've always read that when you tap the brake it is suppose to unlock the converter but mine does not. Should I be able to tap the brake and unlock the converter? What other switches control that besides the brake switch?

TCC solenoid inside the valve body of the transmission controls the torque converter. There is also one wire that runs from the transmission harness up to the ecm, it grounds itself to make the converter lock and unlock. It's about a $40 part, but requires entire removal of valve body and all of it's tiny little internal parts.

I've already changed the tcc solenoid. But didn't know there was another switch in the valve body. You wouldnt happen to have the part number on it? I've also changed the pressure switch, the speed sensor, and put a new torque converter in it ( wanted a tci converter) so whats another 40 bucks right.

The part number I have was out of a 4l60e, and t definately would not be the right one. Alldata would have the diagram of the valve body, and it would be able to give you the exact term and number for that part. I used to have a set of Helm's books for my Silverado, but I got rid of them last year....

For you tranny guys; Is this problem related to the "roaring" noise heard from so many 80E trannys when the engine RPMs get over 2500 or so? Usually heard for several seconds before shifting. A friend of mine had this on a brand new 80E. The dealer kept telling him it was normal. After alot of pestering, a regional GM rep authorized a warranty swap and that fixed the problem for him. Since the issue was brought to my attention at that time, I regularly hear this roaring out of late model 2500s that are no doubt equipped with an 80E.

The sound is very distinctive and loud; I have never heard anything like it from any of the many 60E equipped vehicles I have owned. The roaring went away after his swap and has not returned after (so far) over 100K since.

Has your concern been resolved? Have you brought this to the attention of you local dealer? I would also be willing to take a look into this on my end with the last eight of your VIN. You may feel free to contact me privately. Please keep me posted either way. Thank you.